Formulation and Optimization of Sustained Release Matrix Tablet of Metformin HCl 500 mg Using Response Surface Methodology

Investigating the Role of the Reduced Solubility of the Pirfenidone-Fumaric Acid Cocrystal in Sustaining the Release Rate from Its Tablet Dosage Form by Conducting Comparative Bioavailability Study in Healthy Human Volunteers

Pirfenidone (PFD) is the first pharmacological agent approved by the US Food and Drug Administration (FDA) in 2014 for the treatment of idiopathic pulmonary fibrosis (IPF). The recommended daily dosage of PFD in patients with IPF is very high (2403 mg/day) and must be mitigated through additives. In the present work, sustained-release (SR) formulations of the PFD-FA cocrystal of two different strengths such as 200 and 600 mg were prepared and its comparative bioavailability in healthy human volunteers was studied against the reference formulation PIRFENEX (200 mg). A single-dose pharmacokinetic study (200 mg IR vs 200 mg SR) demonstrated that the test formulation exhibited lower C_max and T_max in comparison to the reference formulation, which showed that the cocrystal behaved like an SR formulation. Further in the multiple-dose comparative bioavailability study (200 mg IR thrice daily vs 600 mg SR once daily), the test formulation was found bioequivalent to the reference formulation. In conclusion, the present study suggests that cocrystallization offers a promising strategy to reduce the solubility of PFD and opens the door for potential new dosage forms of this important pharmaceutical.

Bioequivalence and Safety Assessment of Two Formulations of Metformin Hydrochloride Sustained-Release Tablets (Yuantang® SR and Glucophage® XR) Under Fed Conditions in Healthy Chinese Adult Subjects: An Open-Label, Two-Way Crossover, Sequence Randomized Phase I Clinical Trial

Objective

The purpose of this single-center, randomized, open, two-period, two-sequence crossover, single-dose administration, bioequivalence research was to evaluate the bioequivalence and safety of the generic formulations of metformin hydrochloride sustained-release (MH-SR) 500 mg tablets (test preparation [T]: Yuantang^® SR) and the original formulation (reference preparation [R]: Glucophage^® XR) in 36 healthy Chinese volunteers under postprandial conditions.

Methods

Subjects received 500 mg T/R in each period, with a 7-day washout period. Venous blood samples of 4 mL each were collected from each subject 19 times spanning predose (0 h) to 36 h postdose. The metformin concentration in deproteinized plasma was determined by high-performance liquid chromatography–tandem mass spectrometry. Bioequivalence (80.00–125.00%) was assessed by adjusted geometric mean ratios (GMRs) and two-sided 90% confidence intervals (CIs) of the area under the curve (AUC) and maximum concentration (C_max) for each component. SAS 9.4 software was used for statistical analysis and Phoenix WinNonlin software v7 was used to analyze the pharmacokinetic parameters.

Results

Thirty-four volunteers completed the clinical study. The 90% CIs (96.12–105.44% for AUC from time zero to the time of the last measurable concentration [AUC_t], 96.22–105.54% for AUC extrapolated from time zero to infinity [AUC_∞], and 98.42–105.00% for C_max) of T/R adjusted GMRs were within the bioequivalence acceptance range of 80.00–125.00%, indicating that they are bioequivalent. No serious adverse events occurred in this study, indicating that the two formulations were effective and well tolerated.

Conclusions

Yuantang^® SR was confirmed to be a well tolerated and bioequivalent alternative to Glucophage^® XR when taken under postprandial conditions in healthy Chinese volunteers. The Clinical Trials Registry Platform used for this study was http://www.chinadrugtrials.org.cn/clinicaltrials.searchlistdetail.dhtml. The trial registration numbers (TRNs) and dates of registrations were CTR20180476 (19 April 2018) for this clinical trial and CTR20171595 (11 January 2018) for the pilot trial.

Preparation and characterization of metformin hydrochloride controlled-release tablet using fatty acid coated granules

Metformin hydrochloride (MFM) is often used as a controlled-release (CR) tablet to reduce dosing frequency. However, the MFM CR tablet contains significant amounts of excipients and the tablet size is also large. Dosing convenience and patient compliance can be increased by reducing the size of the CR tablets. The aim of this study was to prepare and evaluate the MFM controlled-release tablet (MFM-CRT) using two types of release modulators, inner and outer. The MFM-CRT was prepared by coating the MFM granules using a binder solution containing aluminum stearate (ALS) as the inner release-modulator, and polyethylene oxide (PEO) as the outer release-modulator. The dispersion stability of the binder solution was optimized by the dispersion analyzer. The MFM-CRT was evaluated for dissolution rate and tablet volume. Additionally, dissolution behavior and dissolution kinetics of the MFM-CRT were analyzed using micro-computed tomography (micro-CT). Although the optimal MFM-CRT showed no difference in the release rate as compared to the commercially available product of Glucophage^® XR 500 mg (f₂ value: 72), the length of the long axis was reduced by 6 mm and the weight was reduced by about 27%. We expect patient compliance to improve because of effective sustained release and volume reduction of MFM-CRT.

Box-Behnken experimental design for preparation and optimization of the intranasal gels of selegiline hydrochloride

Selegiline hydrochloride (SL) is chosen as an adjunct for the control of clinical signs of Parkinsonian patients. The aim of the present work is to develop and optimize thermosensitive gels using Pluronic (F-127) for enhancing transport of SL into the brain through the nasal route. SL gels were prepared using a cold method and the Box-Behnken experimental design methodology. Drug (SL), gelling agent (F-127), and emulsifier (Propylene glycol, PG) were selected as independent variables, while the gelation temperature, gel strength, pH, gel content, and gel erosion were considered as dependent variables. For further understanding of the interaction between the various variables, contour plots and surface plots were also applied. Selected formulations, like S10 (contain 25 mg SL, 20 g F-127, and 1 g PG) and S14 (contain 50 mg SL, 18 g F-127 and 1 g PG), had a clear appearance in the sol form, with gelling temperature of the nasal gel ranging between 33 and 34, respectively. The gel strength of the formulations varied from 4.67 and 0.68 mm and the drug content was 100%. The pH of the formulations ranged between 6.71 and 7.11. Detachment force was acceptable (63.69-244.16 N/cm²) to provide prolonged adhesion. In vitro, drug release studies showed that the prepared formulations could release SL for up to 8 h. Permeation flux for the S10 gel was 0.0002 mg/min/cm². Results demonstrated that the potential use of SL gels can enhance the therapeutic effect of SL through the intranasal administration.

Development and evaluation of in situ gel of pregabalin

Aim and Background:

Pregabalin (PRG), an analog of gamma-aminobutyric acid, reduces the release of many neurotransmitters, including glutamate, and noradrenaline. It is used for the treatment of epilepsy; simple and complex partial convulsion. The present research work aims to ensure a high drug absorption by retarding the advancement of PRG formulation through the gastrointestinal tract. The work aims to design a controlled release PRG formulation which is administered as liquid and further gels in the stomach and floats in gastric juice.

Materials and Methods:

In situ gelling formulations were prepared using sodium alginate, calcium chloride, sodium citrate, hydroxypropyl methylcellulose (HPMC) K100M, and sodium bicarbonate. The prepared formulations were evaluated for solution viscosity, drug content, in vitro gelling studies, gel strength, and in vitro drug release. The final formulation was optimized using a 3² full factorial design.

Results:

The formulation containing 2.5% w/v sodium alginate and 0.2% w/v calcium chloride were considered optimum since it showed minimum floating lag time (18 s), optimum viscosity (287.3 cps), and gel strength (4087.17 dyne/cm²). The optimized formulation follows Korsmeyer-Peppas kinetic model with n value 0.3767 representing Fickian diffusion mechanism of drug release.

Conclusion:

Floating in situ gelling system of PRG can be formulated using sodium alginate as a gelling polymer and calcium chloride as a complexing agent to control the drug release for about 12 h for the treatment of epilepsy.

Experimental design and optimization of raloxifene hydrochloride loaded nanotransfersomes for transdermal application

Raloxifene hydrochloride, a highly effective drug for the treatment of invasive breast cancer and osteoporosis in post-menopausal women, shows poor oral bioavailability of 2%. The aim of this study was to develop, statistically optimize, and characterize raloxifene hydrochloride-loaded transfersomes for transdermal delivery, in order to overcome the poor bioavailability issue with the drug. A response surface methodology experimental design was applied for the optimization of transfersomes, using Box-Behnken experimental design. Phospholipon^® 90G, sodium deoxycholate, and sonication time, each at three levels, were selected as independent variables, while entrapment efficiency, vesicle size, and transdermal flux were identified as dependent variables. The formulation was characterized by surface morphology and shape, particle size, and zeta potential. Ex vivo transdermal flux was determined using a Hanson diffusion cell assembly, with rat skin as a barrier medium. Transfersomes from the optimized formulation were found to have spherical, unilamellar structures, with a homogeneous distribution and low polydispersity index (0.08). They had a particle size of 134±9 nM, with an entrapment efficiency of 91.00%±4.90%, and transdermal flux of 6.5±1.1 μg/cm²/hour. Raloxifene hydrochloride-loaded transfersomes proved significantly superior in terms of amount of drug permeated and deposited in the skin, with enhancement ratios of 6.25±1.50 and 9.25±2.40, respectively, when compared with drug-loaded conventional liposomes, and an ethanolic phosphate buffer saline. Differential scanning calorimetry study revealed a greater change in skin structure, compared with a control sample, during the ex vivo drug diffusion study. Further, confocal laser scanning microscopy proved an enhanced permeation of coumarin-6-loaded transfersomes, to a depth of approximately160 μM, as compared with rigid liposomes. These ex vivo findings proved that a raloxifene hydrochloride-loaded transfersome formulation could be a superior alternative to oral delivery of the drug.

Formulation and in vitro evaluation of mucoadhesive controlled release matrix tablets of flurbiprofen using response surface methodology

The objective of the current study was to formulate mucoadhesive controlled release matrix tablets of flurbiprofen and to optimize its drug release profile and bioadhesion using response surface methodology. Tablets were prepared via a direct compression technique and evaluated for in vitro dissolution parameters and bioadhesive strength. A central composite design for two factors at five levels each was employed for the study. Carbopol 934 and sodium carboxymethylcellulose were taken as independent variables. Fourier transform infrared (FTIR) spectroscopy studies were performed to observe the stability of the drug during direct compression and to check for a drug-polymer interaction. Various kinetic models were applied to evaluate drug release from the polymers. Contour and response surface plots were also drawn to portray the relationship between the independent and response variables. Mucoadhesive tablets of flurbiprofen exhibited non-Fickian drug release kinetics extending towards zero-order, with some formulations (F3, F8, and F9) reaching super case II transport, as the value of the release rate exponent (n) varied between 0.584 and 1.104. Polynomial mathematical models, generated for various response variables, were found to be statistically significant (P<0.05). The study also helped to find the drug's optimum formulation with excellent bioadhesive strength. Suitable combinations of two polymers provided adequate release profile, while carbopol 934 produced more bioadhesion.

Metformin loaded non-ionic surfactant vesicles: optimization of formulation, effect of process variables and characterization

Background

Metformin an oral hypoglycemic has been widely used as a fist line of treatment of Type II Diabetes but in a very high dose 2–3 times a day and moreover suffers from a number of side effects like lactic acidosis, gastric discomfort, chest pain, allergic reactions being some of them. The present work was conducted with the aim of sustaining the release of metformin so as to decrease its side effects and also reduce its dosing frequency using a novel delivery system niosomes (non-ionic surfactant vesicles). Non-ionic surfactant vesicles of different surfactants were prepared using thin film hydration technique and were investigated for morphology, entrapment, in-vitro release, TEM (transmission electron microscopy) and physical stability. Optimized formulation was further studied for the effect of Surfactant concentration, DCP (Dicetyl phosphate), Surfactant: cholesterol ratio and volume of hydration. The release studies data was subjected to release kinetics models.

Results

The prepared vesicles were uniform and spherical in size. Optimized formulation MN3 entrapped the drug with 84.50±0.184 efficiency in the vesicles of the size 487.60±2.646 and showed the most sustained release of 73.89±0.126. Also it was resulted that 100 molar concentration of cholesterol and surfactant, Presence of DCP, equimolar ratio of span 60: cholesterol and 15 ml of volume of hydration were found to be optimum for miosome preparation.

Conclusions

The present work concluded metformin loaded niosomes to be effective in sustaining the drug release leading to decreased side effects and increased patient compliance.

Use of response surface methodology in the formulation and optimization of bisoprolol fumarate matrix tablets for sustained drug release

The aim of this investigation was to develop and optimize bisoprolol fumarate matrix tablets for sustained release application by response surface methodology based on 2³ factorial design. The effects of the amounts of calcium alginate, HPMC K4M, and Carbopol 943 in bisoprolol fumarate matrix tablets on the properties of bisoprolol fumarate sustained release matrix tablets like drug release and hardness were analyzed and optimized. The observed responses were coincided well with the predicted values by the experimental design. The optimized bisoprolol fumarate matrix tablets showed prolonged sustained release of bisoprolol fumarate over 6 hours. These matrix tablets followed the first-order model with anomalous (non-Fickian) diffusion mechanism.

Formulation development and optimization of sustained release matrix tablet of Itopride HCl by response surface methodology and its evaluation of release kinetics

The objective of this present investigation was to develop and formulate sustained release (SR) matrix tablets of Itopride HCl, by using different polymer combinations and fillers, to optimize by Central Composite Design response surface methodology for different drug release variables and to evaluate drug release pattern of the optimized product. Sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: hydroxy propyl methyl cellulose (HPMC) and polyvinyl pyrolidine (pvp) and lactose as fillers. Study of pre-compression and post-compression parameters facilitated the screening of a formulation with best characteristics that underwent here optimization study by response surface methodology (Central Composite Design). The optimized tablet was further subjected to scanning electron microscopy to reveal its release pattern. The in vitro study revealed that combining of HPMC K100M (24.65 MG) with pvp(20 mg)and use of LACTOSE as filler sustained the action more than 12 h. The developed sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet.

Development of cloxacillin loaded multiple-unit alginate-based floating system by emulsion-gelation method

This work investigates the development, optimization and in vitro evaluation of liquid paraffin-entrapped multiple-unit alginate-based floating system containing cloxacillin by emulsion-gelation method for gastro retentive delivery. The effect of process variables like drug to polymer ratio by weight, and liquid paraffin to water ratio by volume on various physicochemical properties in case of liquid paraffin-entrapped calcium alginate beads containing cloxacillin applicable to drug entrapment efficiency, density and drug release was optimized using 3(2) factorial design and analyzed using response surface methodology. The observed (actual values) responses were coincided well with the predicted values, given by the optimization technique. The optimized beads showed drug entrapment efficiency of 64.63±0.78%, density of 0.90±0.05 g/cm(3), and drug release of 56.72±0.85% in simulated gastric fluid (pH 1.2) after 8h with floating lag time of 8.45 min and floated well over 12h in simulated gastric fluid (pH 1.2). The average size of all dried beads ranged from 1.73±0.04 to 1.97±0.08 mm. The beads were characterized by SEM and FTIR for surface morphology and excipients-drug interaction analysis, respectively. All these beads showed prolonged sustained release of cloxacillin over 8h in simulated gastric fluid (pH 1.2). The cloxacillin release profile from liquid paraffin beads followed Korsmeyer-Peppas model over a period of 8h with anomalous (non-Fickian) diffusion mechanism for drug release.

Formulation of a modified release metformin. HCl matrix tablet: influence of some hydrophilic polymers on release rate and in-vitro evaluation

Metformin hydrochloride is an antidiabetic agent which improves glucose tolerance in patients with type 2 diabetes and reduces basal plasma levels of glucose. In this study, a simplex centroid experimental design with 69 runs was used to select the best combination of some hydrophilic polymers that rendered a 24 h in-vitro release profile of metformin.HCl. The Korsmeyer-Peppas model was used to model the dissolution profiles since it presented the best fit to the experimental data. Further, a cubic model predicted the best formulation of metformin.HCl containing polyvinyl pyrrolidone, ethyl cellulose, hydroxypropyl methyl cellulose, carrageenan, sodium alginate, and gum arabic at 6.26, 68.7, 6.26, 6.26, 6.26 and 6.26 % levels, respectively. The validation runs confirmed the accuracy of the cubic model with six components for predicting the best set of components which rendered a once-a-day modified release hydrophilic matrix tablet in compliance with the USP specifications.

Effect of Kollidon® SR on the release of Albuterol Sulphate from matrix tablets

The objective of this study was to evaluate Kollidon SR for the development of extended release Albuterol Sulphate matrix tablets in comparison with other polymers as Hydroxypropylmethylcellulose K15M, Carbopol 71G NF, and Eudragit L100-55. The mechanical properties of the tablets were improved as concentration of Kollidon SR or other polymers increased. It was found that Kollidon SR 30% (w/w) and HPMC 30% (w/w) tablets have f 2 similarity factor of 83.5 in their Albuterol Sulphate dissolution profile. The marketed product was found to release 99.7% of drug content within 8 h, while Kollidon SR and HPMC tablets with 30% (w/w) polymer concentration level released 92.7% and 92.9% respectively of drug content within 8 h. Kollidon SR has a unique character of maintaining tablets geometric shape until the end of dissolution test, this is mainly due to the water insoluble content, polyvinyl acetate, forming 80% (w/w) of Kollidon SR, while the remaining content 20% (w/w) is the water soluble, polyvinylpyrrolidone, responsible for pore formation causing a diffusion controlled release. Drug release from all previous formulations is best described to be controlled by more than one kinetic mechanism of release. In conclusion, Kollidon SR and HPMC and Carbopol were found to be potential candidates for the development of extended release of Albuterol Sulphate tablets.